Tens of thousands of Filipinos have fled their homes around the erupting Mount Mayon volcano.

Philippines officials said about 30,000 people had evacuated the area as ash, lava and rocks the size of small cars spewed from the summit of the conical mountain.

Fourteen explosions had been recorded by late Thursday afternoon, seismologists at the Philippine Institute of Volcanology and Seismology said.

Earlier, a state of emergency was declared and, although there were no immediate reports of casualties, the authorities fear that more than 50,000 people may have to take shelter in evacuation centres.

The entire central province of Albay has been placed under a "state of calamity" which means that money will be made available to shelter and feed the tens of thousands of people who might eventually have to flee.

1000 degrees C

As ash from columns 10km high rained back down to earth, temperatures in the lava flows reached about 1,000 degrees Celsius. In some places the ash was settling on the ground like hot, grey snow.

Volcanic ash shot miles up into the sky

All commercial flights in the area have been cancelled.

The lava was flowing towards the nearby city of Legazpi, although residents were in no immediate danger.

Motorists have been stopping by the side of roads to watch the eruption of the 2,500-metre near-perfect cone-shaped volcano.

Ten-year cycle

Volcanologists say the eruption has been relatively mild so far, but predict that it could become considerably more violent.

Mount Mayon is one of the most active volcanoes in the Philippines, erupting on average once every 10 years.

The volcano has been restive for eight months, and scientists had warned that the increased flows of lava were indicating a build-up in its activity.

Sensitive evacuation

The provincial disaster management authority sent trucks to move local residents.